[PATCH] D151848: [X86, Peephole] Enable FoldImmediate for X86

[Guozhi Wei via Phabricator via llvm-commits]

Carrot added a comment.

In D151848#4600416 <https://reviews.llvm.org/D151848#4600416>, @Carrot wrote:

> In D151848#4597644 <https://reviews.llvm.org/D151848#4597644>, @goldstein.w.n wrote:
>
>> Some codesize/Reg slloc stats from llvm test suite would be useful to have for evaluating the benefit of this patch.
>
> I will collect these stats for spec int 2006.

Here is the related stats for building spec int 2006

  Without this patch
  
  1959884 Number of machine instrs printed
  
  124286 Number of instructions rematerialized
  96962 Number of instructions re-materialized
  82246 Number of instructions deleted by DCE 
  97965 Number of shrinkToUses called
  
  650467 Number of registers assigned
  91796 Number of copies inserted for splitting
  22727 Number of interferences evicted
  20178 Number of splits finished
  9640 Number of folded stack accesses
  829 Number of folded loads
  316 Number of live ranges fractured by DCE 
  13285 Number of split global live ranges
  227433 Number of identity moves eliminated after rewriting
  7536 Number of dead lane conflicts tested
  4074 Number of dead lane conflicts resolved
  1476 Number of split local live ranges
  155548 Number of new live ranges queued
  44378 Number of reloads inserted
  629 Number of reloads removed
  25069 Number of rematerialized defs for spilling
  2255 Number of rematerialized defs for splitting
  9584 Number of splits that were simple
  1156 Number of spilled snippets
  16277 Number of spill slots allocated
  29934 Number of spilled live ranges
  21939 Number of spills inserted
  430 Number of spills removed
  26830 Number of registers unassigned
  612 Number of instruction commuting performed
  169128 Number of cross class joins performed
  13 Number of copies extended
  529170 Number of interval joins performed
  20 Number of register classes inflated
  35 Number of single use loads folded after DCE 

  With this patch
  
  45008 Number of move immediate folded
  
  1959709 Number of machine instrs printed
  
  79327 Number of instructions rematerialized
  52043 Number of instructions re-materialized
  46082 Number of instructions deleted by DCE 
  53046 Number of shrinkToUses called
  
  650311 Number of registers assigned
  91762 Number of copies inserted for splitting
  22698 Number of interferences evicted
  20167 Number of splits finished
  9653 Number of folded stack accesses
  829 Number of folded loads
  315 Number of live ranges fractured by DCE 
  13282 Number of split global live ranges
  227415 Number of identity moves eliminated after rewriting
  7536 Number of dead lane conflicts tested
  4074 Number of dead lane conflicts resolved
  1466 Number of split local live ranges
  155411 Number of new live ranges queued
  44319 Number of reloads inserted
  697 Number of reloads removed
  25035 Number of rematerialized defs for spilling
  2249 Number of rematerialized defs for splitting
  9572 Number of splits that were simple
  1166 Number of spilled snippets
  16272 Number of spill slots allocated
  29925 Number of spilled live ranges
  21900 Number of spills inserted
  446 Number of spills removed
  26800 Number of registers unassigned
  613 Number of instruction commuting performed
  169130 Number of cross class joins performed
  13 Number of copies extended
  529157 Number of interval joins performed
  20 Number of register classes inflated
  35 Number of single use loads folded after DCE 

Conclusion:

1. There was no FoldImmediate occurred without this patch. Now there are 45008 occurrences of FoldImmediate with this patch.

2. There are 175 less instructions generated with this patch.

3. There is significantly less rematerialization occurred, because related immediate are already folded into instructions.

There is no big differences for other stats.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151848/new/

https://reviews.llvm.org/D151848